The impact of migration on the basic parameters of human population biology is poorly known. Previously published data on the subject is generally limited to the effects of migration from poor agricultural settings to industrial urbanized societies. The overall objective of the present study is the analysis and publication of a body of population biology data collected on migrants and natives in an agricultural valley in southern Peru. This data was collected in a manner which permits the analysis of not only the biological impact of migration but also to some extent the effects of such environmental factors as previous environment exposure. The data to be analyzed includes information on such characteristics as fertility, mortality, physical growth, perceived health, nutritional patterns, lung function, and cardiovascular risk factors. Much of the data was collected in family and community units. Thus analysis will include a study of family patterning effects and the effect of migrant destination on biological response.